Taking It To The Track

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Looks like rain tomorrow evening. The only rain in the week's forecast is tomorrow evening. DOH!
I'll go another time.
 
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After several postponements because of potential weather problems, and friends not able to make it, I'm on for tomorrow. Gonna see how all of this time and effort ends up!

Say hi if you're there and you see the car in my avatar!
 
I finally made it to Atco last night and it was an (almost) total success! It went straight and very smooth.

Small issues:
-The first run it stumbled off the line, and I went 1st to 3rd, I also lifted near the top because it was out of breath. (The 4.33's are a bit much, I plan on taller tires) It runs out of steam about 5800. A bigger pump nozzle fixed the stumble.
-On the second run, instead of 1st to 3rd, I short shifted 1-2 somehow. It's a Hurst Quarter Stick, and I have no prior experience with one. (By the 4th run, I was getting more comfortable with it.) I stayed in it, it went to about 6500, though out of breath.
-The third run went perfect.
-The fourth also was nice, it slowed a bit as I went down the track.

The Wallace calculator say it makes 291 hp at 3000#. (car-2760, about 40# more gas in it than when it was weighed, and I'm 200) I thought it makes more. It has a 360 with 11.25:1 comp, 292 purple cam, 915 (I think) ported heads with 2.02 intakes, Holley 750 vac sec, Torker II. (As I bought it, I just took it apart to check it out and put rings and bearings in it.) Maybe the 108 mph isn't accurate because it runs out of steam before the traps, lowering the hp estimate?


I had no idea if it would hook. It did. It has the original .850 torsion bars CE 3 way front shocks, set on "loose", the original slant leaf springs with the front half clamped, and parts store rear shocks. It also has 'glass fenders, hood, bumpers, and the battery in the trunk, helping with weight transfer. It has M/T 235/60 drag radials that are maybe 10 years old!

Having driven it on the street, I got the bugs out of it. I had no idea how it would launch though, since there's no hook on the street.

A friend is sending me pics and video. I've had difficulty posting video before, but I'll try, and get the pics up.
1687368325912.png
 
Icetech said:
Looks good, and the low mph will for sure mess up the hp estimate
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I guess it could be valve springs or fuel delivery, if it's not just plain out of breath.

I have 1/2" fuel from the sock to the Holley regulator (at the front), and a Holley blue pump. 3/8" from the regulator to the carb. I also have a mech. fuel pressure gauge, never thought to look at it. :rolleyes:

Valve spring pressure is one thing I didn't check when I had it apart.
 
pittsburghracer said:
Sounds like a fun night to me. Congratulations on getting it out.
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Thanks, it was a good night all around. I've been waiting a long time for that first pass.
My friends are already trying to get me to enter the Tuesday gambler's race. lol Last time I raced competitively was the mid 90's. I'm not sure about getting into that again. Although I do admit to digging out my old Tag Systems practice tree. Oh boy...
 
SpeedThrills said:
Thanks, it was a good night all around. I've been waiting a long time for that first pass.
My friends are already trying to get me to enter the Tuesday gambler's race. lol Last time I raced competitively was the mid 90's. I'm not sure about getting into that again. Although I do admit to digging out my old Tag Systems practice tree. Oh boy...
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You should . race as offten as possible, car seems consistent for first time out.
 
SpeedThrills said:
I guess it could be valve springs or fuel delivery, if it's not just plain out of breath.

I have 1/2" fuel from the sock to the Holley regulator (at the front), and a Holley blue pump. 3/8" from the regulator to the carb. I also have a mech. fuel pressure gauge, never thought to look at it. :rolleyes:

Valve spring pressure is one thing I didn't check when I had it apart.
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3.23's with 7 X 27" slicks. 25.5-26" would have been great with that gear.
 
I have a theory on it laying down at the top end.
When I use the 8th mile numbers from my time slip in the Wallace calculator, it shows 350 hp compared to the 291 when I use the quarter-mile numbers. That shows the 108 ain’t right. Wallace shows 113 when I use 350 hp.
I put a 2.5 power valve in it when I was trying to get it to idle. I’m thinking that maybe it is closing at the top end. I’m gonna run it with a vacuum gauge and take a different power valve next time.
I have to see what vacuum it has in gear. It’s only 5” in park. I’m hoping a 3.5 will work, if the pv is the problem.
 
congrats for your 11 seconds time slips on the first time out. 5 in. of vacuum idling in park aint much, your power valve is probably open all the time. also, from your et, you should be going 115 mph or so , as you already know. i suspect that this 3310 is where you could improve. if you could borrow a double-pumper that is in good shape... look at the vacuum reading with the double pumper, it should go up. if vacuum doesnt improve, try twisting the distributor. that 508 cam will like a lot of initial advance. none of this costs money. have fun! and be ready for personnal bests!
 
7e5hangten360 said:
congrats for your 11 seconds time slips on the first time out. 5 in. of vacuum idling in park aint much, your power valve is probably open all the time. also, from your et, you should be going 115 mph or so , as you already know. i suspect that this 3310 is where you could improve. if you could borrow a double-pumper that is in good shape... look at the vacuum reading with the double pumper, it should go up. if vacuum doesnt improve, try twisting the distributor. that 508 cam will like a lot of initial advance. none of this costs money. have fun! and be ready for personnal bests!
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Thanks for the kind words.
I took out a 6.5 and installed the 2.5 I mentioned while tuning it on the street, before I went to the track. That and a few other things has it idling in gear now. Next, I'll install PV rated a bit higher than any vacuum reading I get through the traps. I have to hope that PV won't open at idle, in gear. That's why I have to see what vacuum it has in gear, idling. After that, from what I read in Dave Emanual's, "Super Tuning and Modifying Holley Carbs", I'll have to try a combination of blocking the PV, richening the jets, and making the idle feed restrictions smaller.
That's what I see. If anyone has other ideas, I'm here to listen!

I don't know anyone to borrow a carb from, but I think I have to make mine work. But I suppose it could have a vacuum leak in it. I haven't found any leaks anywhere.
What would make a double pumper have a higher vacuum reading than a vacuum secondary?

My distributor is set at 35* total, with a lot, probably 25-28* initial (all in quick), also aimed at getting it to idle. I also have an ignition kill switch so that it'll spin when starting hot.
 
I remember guys on here saying Holley had it wrong on power valves. Correct way is to measure vacuum at cruise RPM and divide that instead of idle. I'm sure somebody else with more experience will chime in. Here's an old thread on power valves

www.forabodiesonly.com

Power Valve Selection: The Definitive Answer

There are varying opinions on how one goes about selecting a power valve for Holley based carbs (as anyone who has worked on one well knows) There's the 1/2 of idle vacuum, either with 4-speed in neutral or auto in drive, the more widely accepted 2" less than cruise vacuum, I've also seen people...
www.forabodiesonly.com www.forabodiesonly.com
 
Boosters don't flow at idle and that's where the PVCRs flow the extra fuel.
Put a fuel pressure gauge you can see or video. Laying down on the big end may be lack of fuel flow.
I would also get rid of the 10 year old tires.
 
here is how i set the power valve on my holleys: with the engine hot, i let the car idle IN GEAR and take a reading of the vacuum. that is most likely the lowest vacuum reading you will get. then i choose a power valve with 2 numbers less than that reading (that is the old fashioned-way but it works). that way, it will not open unless going wide open throttle or when accelerating. note that the number of doors (or openings) of the p.v. plays a big role when accelerating. a regular p.v. has 2 small holes from holley most of the time. going to a 2 door (2 rectangular openings) pv will richen up the mixture under acceleration. a 4-door pv will richen it up even more. also, make sure the p.v. you chose hasnt dried up, that would mess-up your calibration.
what i meant about more vacuum reading for a double-pumper is that it will make more vacuum than the current carb, if it is not running right. also, out of 3 vacuum-secondary 3310`s i had, only one was on par with a 750 double-pumper on my car.
also, if you removed the choke, there is a chance you have a vacuum leak where the choke mechanism was. mostly occurs on carbs with ELECTRIC choke beeing removed.
 
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mderoy340 said:
Boosters don't flow at idle and that's where the PVCRs flow the extra fuel.
Put a fuel pressure gauge you can see or video. Laying down on the big end may be lack of fuel flow.
I would also get rid of the 10 year old tires.
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I may be confusing the possible PV issue with having a blown PV? Is that when it'll run rich at idle?
I shifted about 5800, but it was going to about 6500 in the traps, and maybe is pulling vacuum and closing the PV, if I'm thinking right.

Post #9 explains my fuel system, of course, there still could be an issue.

Yeah, I know about the tires.
 
7e5hangten360 said:
here is how i set the power valve on my holleys: with the engine hot, i let the car idle IN GEAR and take a reading of the vacuum. that is most likely the lowest vacuum reading you will get. then i choose a power valve with 2 numbers less than that reading (that is the old fashioned-way but it works). that way, it will not open unless going wide open throttle or when accelerating. note that the number of doors (or openings) of the p.v. plays a big role when accelerating. a regular p.v. has 2 small holes from holley most of the time. going to a 2 door (2 rectangular openings) pv will richen up the mixture under acceleration. a 4-door pv will richen it up even more. also, make sure the p.v. you chose hasnt dried up, that would mess-up your calibration.
what i meant about more vacuum reading for a double-pumper is that it will make more vacuum than the current carb, if it is not running right. also, out of 3 vacuum-secondary 3310`s i had, only one was on par with a 750 double-pumper on my car.
also, if you removed the choke, there is a chance you have a vacuum leak where the choke mechanism was. mostly occurs on carbs with ELECTRIC choke beeing removed.
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Yes, I need to see what vacuum it has in gear, at idle. (I'll also check cruise vacuum.) And also see if it's pulling vacuum at the top end, and try to use a PV that won't close at the top end. If it's not closing the 2.5 that's in it, none of this matters and I need to look elsewhere!

Thanks for the info about PV flow, I plan on getting a hi-flow.

I'll see if this carb has any problems. I just can't swing a 750 DP. Plus, my converter is about 3200ish. Would a DP be sluggish with that tight a converter?

I rebuilt the carb when I put the engine in, maybe 3 years ago. Yes, I removed the electric choke. I'll have to see if the vacuum source for the choke is still plugged. I don't remember how I did it, but I'm sure I did. But then again... old fatritus has been kicking in. lol
 
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SpeedThrills said:
I may be confusing the possible PV issue with having a blown PV? Is that when it'll run rich at idle?
I shifted about 5800, but it was going to about 6500 in the traps, and maybe is pulling vacuum and closing the PV, if I'm thinking right.

Post #9 explains my fuel system, of course, there still could be an issue.

Yeah, I know about the tires.
Click to expand...
You really need to read this thread to understand how a power valve operates. Vacuum keeps a power valve closed.
Power Valve Selection: The Definitive Answer
A blown power valve will pull fuel through the vacuum port and make an engine run pig rich at idle.
I run a 9.5 valve in my 340. Cruise vacuum is 14-15, roll the throttle and the power valve opens. This allows you to run a smaller primary jet at cruise. My PVRCs are .064 and 72 jets up front on a Demon 750DP
 
mderoy340 said:
You really need to read this thread to understand how a power valve operates. Vacuum keeps a power valve closed.
Power Valve Selection: The Definitive Answer
A blown power valve will pull fuel through the vacuum port and make an engine run pig rich at idle.
I run a 9.5 valve in my 340. Cruise vacuum is 14-15, roll the throttle and the power valve opens. This allows you to run a smaller primary jet at cruise. My PVRCs are .064 and 72 jets up front on a Demon 750DP
Click to expand...
I scanned that thread last night. I’m going to read it more closely.

I know vacuum holds it shut. Writing about this is harder than talking about it!

So yes, I was confusing a leaking PV with one that just may be open at idle, or whatever vacuum/rpm.

Thanks for the help. I’ll update after some learning and experimenting.
 
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